Previous owners at our house put a couple ac vents in the garage. It gets heated or cooled same as the house. Insulated garage door. Check with an AC guy and see if that's an option

I have one in my home office, which is off the garage. I love it. If I was building a house, I’d install these all over it instead of HVAC. The cool or heat a room down in no time, and are quiet. Wouldn’t need to run forced air through the whole house all the time.

1st world problem.

I've seen a few recommendations of installing AC vents in the garage or some type of exhaust fan or vent registers. Not really a good idea as it is a residential building code violation and a fire hazard. Many home fires start in the garage. Heat rises as does flame and the fire can easily breach the openings in the ceiling spreading to the attic. Once in the attic the fire can easily spread due to the increased air circulation through the roof vents.